1. Field of the Invention
The present invention teaches a discrete flexible pixel element for use in flexible pixel strings and, more particularly, a fabrication method and means for hermetic sealing of discrete flexible pixel elements.
Flexible pixel elements may be used in large scale, direct view electronic display devices and signage mounted on large area and/or irregular surfaces, such as the interior or exterior of buildings, where the intent is to complement the surface architecture of the building by conforming to the building surfaces. A particular problem arises with electronic display devices used in outdoor or exterior displays such as signs since delicate electronic components in such displays are exposed to the detrimental effects of environment, rough handling and inclement weather and are therefore vulnerable to failure. The discrete flexible pixel element, fabrication method and means for hermetic sealing of the present invention precludes failure of electronic components due to the detrimental effects of environment, thereby enabling efficient, economical production of large scale, direct view electronic display devices, signage and lighting effects for outdoor use.
2. Description of the Prior Art
Electronic display devices and signage are known in the art. An electronic display device typically comprises a display board that produces visual images by means of a grid of small light emitting elements, such as incandescent bulbs, LEDs, or the like; data handling and control means for managing transfer of digital image data for display as visual output images, and means for converting digital image data into visual image data and display control signals to drive the light emitting elements, or pixels, to thereby produce visual output images on the electronic display devices for viewing.
The sophistication of visual images that can be displayed on electronic display devices is generally dependent on the capabilities of the light emitting elements, or pixels, used to produce visual images. Light emitting display technology has become increasingly more advanced in the art, progressing from monochrome incandescent and LED devices to video quality components capable of exhibiting near continuous tone visual output, complex animations and live video streams. Improvements in light emitting display technology, including light emitting elements, have in turn enabled the manufacture of electronic display devices that are increasingly large in scale and more powerful in terms of the complexity and sophistication of the visual output images that can be displayed.
Electronic display devices and signage sited in outdoor locations, such as on the exterior surfaces of buildings, are also known in the art. Outdoor electronic display devices and signage are commonly sited near public venues where the visual output images they exhibit may be viewed simultaneously by large numbers of people in groups. Outdoor electronic display devices provide a valuable service to the public since they can provide timely or time-critical information, such as stock and commodity prices, traffic and weather conditions, hazard alerts, and other important information. One popular type of outdoor electronic display device is a large scale video for advertising displays and signage where commercial messages are broadly and effectively exhibited for public viewing.
An inherent problem in the design and manufacture of large scale electronic display devices for outdoor use is the need to protect delicate and vulnerable internal electronic components from failure due to the detrimental effects of environment. This problem is exacerbated by the increasing sophistication of light emitting elements and their collateral support electronics, such as the electronic drivers for the light emitting elements. In the early art, incandescent bulbs served as light emitting elements. Incandescent bulbs are comparatively inexpensive to use, robust in operation and easy to replace; moreover, they require few and comparatively inexpensive collateral support electronics and power and signal conductors. More advanced light emitting elements or pixels, such as LEDs and LCDs, are more expensive to use and replace. In addition, they require more numerous and more expensive collateral support electronics, including pixel element drivers, data buffers, control signal handlers, over-voltage and transient protection circuits, to name a few. Furthermore, advanced light emitting elements and collateral support electronics are comparatively much more delicate and easily damaged by electrostatic shock, thermal shock, mechanical shock, moisture and humidity, and various other detrimental environmental conditions. Advanced light emitting elements and collateral support electronics also require more sophisticated means of mounting and electrical connection, such as surface mounted printed circuit boards (PCBs), as well as more sophisticated means of supplying operating power, digital image data and display control signals, which means greatly increase the number of signal paths and conductors needed to service components and thereby greatly increase the number of connection points and potential points of failure. Therefore, the use of advanced light emitting elements, while presenting advantages in terms of the sophistication of visual output images that can be displayed, also presents a vulnerable design architecture with many potential points of failure.
In the prior art, light emitting elements are collectively sealed within enclosures to protect them from the outside environment. Not only does this add to the cost of producing already expensive large scale outdoor electronic displays and signage, but such enclosures are generally effective only for conventional, rectilinear or planar displays mounted on flat surfaces. Producing collective enclosures that conform to irregular shaped surfaces can be a complex and costly undertaking. Moreover, a collective enclosure typically embodies a single-point failure mode, wherein any failure of the collective enclosure exposes all the light emitting elements, collateral support electronics and connection points contained therein to potential failure. Finally, collective enclosures are subject to overheating from both internal and external sources, including component power dissipation and solar radiation.
A solution to some of these problems is taught in co-pending U.S. utility patent application entitled “Flexible Pixel Element and Signal Distribution Means”, application number to be assigned, filed concurrently herewith, a copy of which is attached and the disclosure of which is incorporated by reference as if fully set forth herein. A portion of that teaching is the use of a plurality of discrete flexible pixel elements that can be interchangeably connected in series by means of flexible cables to produce flexible pixel strings that are conformable to irregular shapes and surfaces.
The present invention further discloses means and methods that are operative and efficacious in manufacturing discrete flexible pixel elements, including a fabrication method and means for encapsulating pixel element electronics, such as light emitting elements and collateral support electronics, and encasing the encapsulated pixel element electronics in an external top encasement cover in order to produce a unitary, hermetically sealed, self-contained module that is protected from the detrimental effects of the environment. The present invention also discloses means for connecting power and signal cables to a plurality of discrete flexible pixel elements in series connection, whereby electrical conductors and contacts within power and signal cables are similarly protected.
In summation, the prior art is generally dependent on conventional means, such as collective enclosures, to protect pixel element electronics used in electronic display devices sited outdoors from preventable failure and damage. Conventional collective enclosures are not well suited for protecting electronic display devices that conform to irregular shapes and surfaces since they are difficult and expensive to fabricate. Furthermore, they embody a single point failure mode which exposes all internal components and connections to potential failure, as well as being subject to overheating. As a result, production of such enclosures is cost prohibitive, while outcomes are often inelegant and failure prone. A novel approach to address the aforesaid deficiencies of the prior art is needed to continue to satisfy public demand and thereby ensure continuing development of the art.